1. Field of Invention
The present invention relates to a hydraulic pressure control apparatus for an automatic transmission and a control method thereof. More particularly, the present invention relates to a hydraulic pressure control apparatus for an automatic transmission, and a control method thereof, that is provided with two oil pumps.
2. Description of Related Art
Generally, an automatic transmission includes a torque converter and a powertrain. In addition, the powertrain realizes multiple shifts by being connected with the torque converter. Further, a hydraulic pump (electric oil pump) is provided so as to supply operating pressure to the automatic transmission, and a TCU (transmission control unit) is provided so as to control operation of the automatic transmission.
The hydraulic pump should be operated at an optimal rotation speed so as to generate a necessary operating pressure for the automatic transmission. Conventionally, a data map of the rotation speed is predetermined so as to generate a target hydraulic pressure, a hydraulic pressure sensor detects whether the operating pressure reaches the target hydraulic pressure, and the motor rotation speed is controlled by feedback of the detected value.
Because the hydraulic pressure sensor having high accuracy and durability is required for the hydraulic pressure control method according to the prior art, the production cost may be increased. In addition, the hydraulic pressure cannot be normally detected and a malfunction of the feedback control may occur due to fluctuation or vibration of hydraulic pressure.
Further, according to the prior art where the data map is predetermined, power loss may be increased since a criterion is determined by considering deviation of the hydraulic pump and the hydraulic pressure sensor. Furthermore, it may be impossible to control the pump by reflecting or compensating deterioration of durability and performance.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.